As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER BOTH ENG'S STARTED ADP PRESS LGT ILLUMINATED PRESS LGT STAYS ILUMINATED WITH SELECTOR SWITCH IN ON POSTION .AC RETURNED TO THE GATE , MAINTENACE GROUNDED AC DEFERRED ADP FOR DEPARTURE IAW MEL ABX-29-11-3. RETURENED AC TO SERVICE AND DEPARTED. WILL AMEND AFTER REPAIR